<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        body {
            display: flex;
            justify-content: center;
            align-items: center;
            width: 100%;
            height: 100vh;
            background-color: grey;
        }

        #color {
            width: 100px;
            height: 100px;
            background-color: cyan;
        }
    </style>
</head>
<body>
    <div id="color"></div>
</body>
</html>
